Phylogenetic tree of nucleotide-sugar transporters. The amino acid sequences of previously characterized NSTs and putative GFT of Schistosoma mansoni (RefSeq/GenBank accession numbers in Table 2) were included in a phylogeny annotated with substrate specificity data. Posterior probabilities are indicated at each node, and genetic divergence (substitutions per site) is represented by the scale bar. Family 3 NSTs , which include transporters of GDP-L-fucose, are labeled on the right. To demonstrate the topology of NST families 1 and 2, these data are also presented as a rooted tree in (Additional file 3: Figure S2). UDP-Xyl, UDP-D-xylose; UDP-GlcNAc, UDP-D-N-acetylglucosamine; UDP-Glc, UDP-D-glucose; UDP-GlcA, UDP-D-glucuronic acid; UDP-GalNAc, UDP-D-N-acetylgalactosamine; UDP-Gal, UDP-D-galactose; GDP-Fuc, GDP-L-fucose; GDP-Man, GDP-D-mannose; GDP-Ara, GDP-D-arabinose; CMP-Sia, CMP-sialic acid.